0

The problem is that all Object attributes apart from 'name' call the error 'id/url/whatever is not defined' in the console when accessed from the template. A template with just 'name' displays fine and shows the correct name, but as soon as I call a different attribute, eg. id or url, it breaks. The object passed to the view is a parsed static JSON file with all items sitting on the same level and accessible from the console with e.g. collectionName.models[0].get('id');

What has me confused is that the name attribute works, as if it is predefined somewhere in backbone/underscore code as a default.

Am I missing something very obvious? Since I can access the model data from the console, I think that there's something wrong with how the view itself handles the data, but I've tried rewriting it in a couple different ways and nothing seemed to make any difference.

All the relevant code.

Passed object format. This is also what collectionName.models[0].attributes; returns in the console.

[{
"id":"0",
"name": "Building1",
"url": "building_1",
"floors":[{
    "id":"0",
    "name":"Ground Floor",
    "image":"",
    "rooms":[{
        "id": "r_1",
        "name": "Room 1",
    },
    {
        "id": "r_2",
        "name": "Room 2"
    }]
}
}]

}

Example template code:

<span class="name"><%= name %></span>
<%= id %> <%= url %>

The router code: 

routes: {
  '': 'intro', // this route is using pretty much identical code and works fine, the model has the exact same format, the only difference is that all attributes work.
  ':id': 'firstLevel'    
},

firstLevel: function  (id) {
  window.singleBuilding = new ThisBuilding({}, {idBuilding: id});

  window.singleBuilding.fetch();      

  this.floorView = new FloorList({
    collection: window.singleBuilding
  });

  var $intro = $('#intro');
  $intro.empty();
  $intro.append(this.floorView.render().el);
}

Views: 

window.FloorSingleList = Backbone.View.extend({

  className: 'floor-list',

  initialize: function  () {

  this.template = _.template(tpl.get('floors-list-item')); 
  _.bindAll(this, 'render');
  this.model.bind('change', this.render);
  this.testModel = this.model.attributes; // I tried passing the attributes directly to the templatewithout .toJSON(), which worked exactly the same, as in only the 'name' attribute worked
},

render: function  () {
  console.log("The test data is:", this.testModel);
  console.log("The actual model data is:", this.model);
  var renderedContent = this.template(this.model.toJSON());
  $(this.el).html(renderedContent);

  return this;
 }

});

window.FloorList = Backbone.View.extend({

tagName: 'section',
className: 'intro-list',

initialize: function () {

  this.template = _.template(tpl.get('intro-list'));
  _.bindAll(this, 'render');
  this.collection.bind('reset', this.render, this);
  this.collection.bind('change', this.render, this);
},

render: function  (eventName) {

     var $introList;
     var collection = this.collection;

  $(this.el).html(this.template({ }));
  $introList = this.$('.intro-list');
  collection.each(function (building) {
    var view = new FloorSingleList({
      model: building,
      collection: collection
    });
    $introList.append(view.render().el);
  });

  return this;
}

});

Model code:

window.ThisBuilding = Backbone.Collection.extend({

model : Building,

initialize: function(models, options) {
  // Initialising the argument passed on from the router.
  this.idBuilding = options.idBuilding;
  return this;
},

url : function(){
  return  "data.json"      
},

parse: function (response) {
  console.log("Passed parameters are :", this.idBuilding); // Returns the request parameters passed from the router.
  return response[this.idBuilding];
}

});

Templates & Bootstrap

// templates are loaded during the bootstrap 
tpl.loadTemplates(['header', 'intro-list', 'floors-list-item', 'building-list-item'], function() {
    window.App = new ExampleApp();
    Backbone.history.start();
});
4

1 回答 1

0

The problem is in how fetch in javascript is asynchronous...

firstLevel: function  (id) {
  window.singleBuilding = new ThisBuilding({}, {idBuilding: id});

  window.singleBuilding.fetch();  // YOU FETCH HERE     

  this.floorView = new FloorList({
    collection: window.singleBuilding
  });

  var $intro = $('#intro');
  $intro.empty();
  $intro.append(this.floorView.render().el); // AND RENDER WHILE YOU CAN'T ASCERTAIN THE FETCH HAS BEEN COMPLETED...
}

So what happens is that the render tries to read a collection that hasn't yet been initialized properly -> your models are not complete yet -> funny readings. Console log works with black magic when regarding to async operations. so it probably tells you something and the reality is something completely different So do this instead:

firstLevel: function  (id) {
  window.singleBuilding = new ThisBuilding({}, {idBuilding: id}); 

  // Don't fetch here...   

  this.floorView = new FloorList({
    collection: window.singleBuilding
  });

  var $intro = $('#intro');
  $intro.empty();
  $intro.append(this.floorView.el); // Don't render here
}

And then in the FloorList-view:

initialize: function () {

  this.template = _.template(tpl.get('intro-list'));
  _.bindAll(this, 'render');
  this.collection.bind('reset', this.render, this);
  this.collection.bind('change', this.render, this);
  this.collections.fetch(); // fetch here, your binds take care of rendering when finished
}

Update 2: Apparently I saw complexity where there was none... Ignore everything below

From Backbone.js docs, on Model.toJSON()

Return a copy of the model's attributes for JSON stringification.

So it returns the attributes as JSON. Now backbone defines id as

A special property of models...

A property, not an attribute. Same goes for url. In a javascript object that represents a backbone Model, the attributes are stored in their own object within the object and the id- and url-properties are stored elsewhere in the model-object. For example the javascript object representing your model could look something like this:

{
  ...
  attributes: Object // this is where your name attribute lives
  ...
  id: 34, // this is your id property
  ...
  __proto__: ctor, // this is where your url-function resides
  ...
}

UPDATE: The id-property is embedded onto the JSON in model.toJSON()

So when you do this.model.toJSON(), you create a JSON from the contents of your model-objects attributes-property and include the id-property. The url -property is not included in this. What you can do for example:

var renderedContent = this.template({
  attributes: this.model.toJSON(),
  url: this.model.url()
});

and in the template

<span class="name"><%= attributes.name %></span>
<%= attributes.id %> <%= url %>

Hope this helps!

于 2012-07-31T12:16:13.147 回答